Help! 04 CS sounded like a diesel this morning - piston slap
10-27-2014, 01:56 PM
#16
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In my book, for the 4.8L engines, Porsche recommends 0W-40 for all temperatures, and 5W-40 and 5W-50 for temperatures above -13F. For a Porsche that will never see -13F, then they think a 5W-50 is OK. Obviously, synthetic oils are readily available in 10W-40 & 15W-40 & 15W-50. One advantage of a more viscous oil is it will drain more slowly, generally leaving the piston walls a little better lubed for starting. A disadvantage is you might see a slight decrease in fuel economy with more viscous oils, which is one reason mfrs recommend low vis oil. They would have to show lower EPA fuel economy ratings if they recommended more viscous oils.. Another issue is whether you are burning oil. As oil consumption increases in an older engine with high mileage, it is usually advisable to use a more viscous oil. You will have to make the decision.
10-28-2014, 07:11 PM
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Ummmm, the "point" is to unload the car while its still running well.
Ummmm, if you can change your oil the you can do a compression test. Obviously your to lazy and negative to google "compression test" to see whats involved. Loud mechanical noise on startup is never good. Im not screaming ebola, but if you have been around people that are likely to have it, you may want to get tested.
Ummmm, if you can change your oil the you can do a compression test. Obviously your to lazy and negative to google "compression test" to see whats involved. Loud mechanical noise on startup is never good. Im not screaming ebola, but if you have been around people that are likely to have it, you may want to get tested.
http://www.enginebasics.com/Engine%2...on%20Test.html
10-28-2014, 07:18 PM
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In my book, for the 4.8L engines, Porsche recommends 0W-40 for all temperatures, and 5W-40 and 5W-50 for temperatures above -13F. For a Porsche that will never see -13F, then they think a 5W-50 is OK. Obviously, synthetic oils are readily available in 10W-40 & 15W-40 & 15W-50. One advantage of a more viscous oil is it will drain more slowly, generally leaving the piston walls a little better lubed for starting. A disadvantage is you might see a slight decrease in fuel economy with more viscous oils, which is one reason mfrs recommend low vis oil. They would have to show lower EPA fuel economy ratings if they recommended more viscous oils.. Another issue is whether you are burning oil. As oil consumption increases in an older engine with high mileage, it is usually advisable to use a more viscous oil. You will have to make the decision.
10-28-2014, 07:21 PM
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Sure you are. You've seized on total engine failure without the facts to back it up. Could it be? Sure.. but before panicking it would make sense to check the easier/cheaper/simpler things first.. and that involves hooking the P!G up to a code reader and looking for stored misfire faults. If you've been around P!Gs for long - you'd realize that is WAY WAY more likely a scenario (especially given the clue of starting and shutting the car off to move it out of the garage) then a scored cylinder.
Sometimes it IS the simple stuff. I like to start there and save panic for when it's needed.
BTW - calling someone "lazy" could be construed as a personal attack on most forums - and usually isn't much liked, by other forum members and the forum management. It also turns everyone off to whatever else you might have to offer, which might actually be good information.
Sometimes it IS the simple stuff. I like to start there and save panic for when it's needed.
BTW - calling someone "lazy" could be construed as a personal attack on most forums - and usually isn't much liked, by other forum members and the forum management. It also turns everyone off to whatever else you might have to offer, which might actually be good information.
10-28-2014, 10:38 PM
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Yes - - for some reason Cayenne's aren't turning on the CEL with misfires. I'm guessing that's intentional on Porsche's part given the crappola coils the engines are fitted with. There can well be some stored misfire codes with no CEL. The only way to find them is to hookup diagnostics. I'd suggest Durametric - since it's Porsche specific. Not sure if a standard OBD-II code reader will catch the stored codes (should, but.. OBD-II standardization is frequently bastardized by euro manufacturers.)
10-28-2014, 10:44 PM
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Would the method described here (using a handheld gauge) work? If so, i'll buy one of these gauges and check it. I see your point about unloading the car.
http://www.enginebasics.com/Engine%2...on%20Test.html
http://www.enginebasics.com/Engine%2...on%20Test.html
Also - disconnect all the coils from the wiring harness.. you don't want a coil firing in air - the kickback to the primary circuit can easily fry the electronics. plus if you don't the other cylinders will fire off and the engine will start. Or find the fuse that kills the ignition circuits and disable them. You could also prevent it from starting by removing the fuel pump fuses then run the engine until it stalls (it will stall very quickly.)
It's also only an accurate test if you open the throttle-body fully open. With an electronic throttle body this requires someone in the vehicle holding the pedal down.
Doing a compression test on a modern engine isn't something as simple as changing the oil IMHO. And I'm willing to bet you'll have a CEL when you're done (even Porsche can't ignore multiple cylinders not firing.)
10-29-2014, 01:25 PM
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Be simple enough to get the ECU stored codes read before going into panic mode. If there are none - then it's time to do the compression test.
10-29-2014, 02:18 PM
#24
Get one with a long screw-in connector to the plug hole. The plugs live in a well in the cylinder head, the old fashioned press-it-in-the-hole ones are worthless for this sort of design.
Also - disconnect all the coils from the wiring harness.. you don't want a coil firing in air - the kickback to the primary circuit can easily fry the electronics. plus if you don't the other cylinders will fire off and the engine will start. Or find the fuse that kills the ignition circuits and disable them. You could also prevent it from starting by removing the fuel pump fuses then run the engine until it stalls (it will stall very quickly.)
It's also only an accurate test if you open the throttle-body fully open. With an electronic throttle body this requires someone in the vehicle holding the pedal down.
Doing a compression test on a modern engine isn't something as simple as changing the oil IMHO. And I'm willing to bet you'll have a CEL when you're done (even Porsche can't ignore multiple cylinders not firing.)
Also - disconnect all the coils from the wiring harness.. you don't want a coil firing in air - the kickback to the primary circuit can easily fry the electronics. plus if you don't the other cylinders will fire off and the engine will start. Or find the fuse that kills the ignition circuits and disable them. You could also prevent it from starting by removing the fuel pump fuses then run the engine until it stalls (it will stall very quickly.)
It's also only an accurate test if you open the throttle-body fully open. With an electronic throttle body this requires someone in the vehicle holding the pedal down.
Doing a compression test on a modern engine isn't something as simple as changing the oil IMHO. And I'm willing to bet you'll have a CEL when you're done (even Porsche can't ignore multiple cylinders not firing.)
All good advice. One thing to keep in mind is that if you do not run the engine out of fuel and disconnect the pump fuses, you can
A: wash the cylinders down with raw fuel, causing more damage.
B: RUIN the cats.
Also, if you find a cylinder not within about ten percent of the others, you can squirt some heavyweight motor oil into the cylinder and if the compression rises that means your cylinder/rings have been compromised on that hole. If it does not rise that would point to valves/seats.
10-29-2014, 02:26 PM
#25
Once you get a compression test off and get satisfactory results, then you can continue to work on and drive the vehicle with some sense of piece of mind.
Beleive me when I say Jonathan and I really do care.
10-29-2014, 10:45 PM
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In my book, for the 4.8L engines, Porsche recommends 0W-40 for all temperatures, and 5W-40 and 5W-50 for temperatures above -13F. For a Porsche that will never see -13F, then they think a 5W-50 is OK. Obviously, synthetic oils are readily available in 10W-40 & 15W-40 & 15W-50. One advantage of a more viscous oil is it will drain more slowly, generally leaving the piston walls a little better lubed for starting. A disadvantage is you might see a slight decrease in fuel economy with more viscous oils, which is one reason mfrs recommend low vis oil. They would have to show lower EPA fuel economy ratings if they recommended more viscous oils.. Another issue is whether you are burning oil. As oil consumption increases in an older engine with high mileage, it is usually advisable to use a more viscous oil. You will have to make the decision.
10-29-2014, 10:51 PM
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10-30-2014, 01:20 PM
#29
I am also not trying to be a dick... I just think you should put more thought into what Haney is trying to say. He is not trying to lead you astray.
Additionally, I didn't see there were 2 pages to this thread... the suggestion to read codes is not a bad one and certainly won't cause any harm.
But without compression/leakdown test you really are flying blind. Codes only tell you so much...
JR
Additionally, I didn't see there were 2 pages to this thread... the suggestion to read codes is not a bad one and certainly won't cause any harm.
But without compression/leakdown test you really are flying blind. Codes only tell you so much...
JR